The isotopic composition of atmospheric carbon dioxide (δ 13 C atm ) provides insights into the terrestrial carbon cycle. However, long‐term global δ 13 C atm maps with both high spatial resolution and continuous temporal coverage remain scarce. Here, we present a new global terrestrial dataset of monthly δ 13 C atm isoscapes from 2001 to 2020 at 0.05° spatial resolution, developed by integrating in situ observations with opti...